Sealing compound



R. H. scHRol-IE ETAL l 2,324,729

` SEALI-NG COMPQUND July zo, 1943..l

Filed Mann 12, 1941] loo Aww/van FLAfrEJ W position. l

mbe construed@ elimimimdescfibuo "wurb tnreededpipe Joints. `The particular xniautemgil` provide a. "thread compound having lflid" Seilinzg*` `properties?evemwhen` used with relati ely coarse 4 20 another.

cal` reagents, both hot;

` Because offlitheseliservice; onqition t x materiaiuernpioyedmystihavefspe i that a slight amount of `oil which may exist initially on the threaded surfaces will not lower its efficiency; (6) it must be of such chemically inert and solvent resistant character that its effective ingredients will not be leliminated under con' tinued use; (7) it must be of such physicalcondition as to be readily applied to the entire surfaces which are to be treated by menas of a brush, spray, dipping or any other suitable method; `and (8) in the event that the material is to be applied by spraying, it must be soluble inl a commercial solvent material in order to bev thinned to the proper consistency. These requirements are of course not exclusive of the other usual requirements which are Well known to those familiar with sealing-materials of this general classification,

ically resistant, finely divided vflake-like material,` mica flakes for instance. Specifically, we have had favorable results with flake aluminum of the following grain size: 140 mesh and finer, 65% of which will pass through a 300 mesh screen.

The third and last of the mentioned ingredients may be any powdered or finely crystalline material which will fill the minute interstices between the flake material and thus seal off finally even the tiniest channels of leakage which may exist between the threaded surfaces around the relatively larger flaky elements. While we give powdered barium sulphate as an example herein this must be understood to be only by way of illustration, since any other chemically inert, insoluble powdery substance may also be used. l We have found that oil by itself, regardless of its `high'viscosity or highly adherent properties, cannot be depended upon to make a threaded joint leak-proof, and neither are satisfactory 4 results obtainable by combining the oil with It is evident, then, that if any of the ingredients which are desired to make a pressure-tight joint in the first instance are leached out by solvent action of the fluid within the pipe, deleterious results will -be obtained to the extent that the joint may leak: and the threaded surfaces may gall when unthreading is attempted. l

The sealing compound'with which our invention is particularly concerned includes the com-v., l

bination of three ingredients, each of which contributes its own specific function in producing a fluid-tight threaded joint. Generally speaking, .we have combined (1) a lubricant having strong adhesion to metallic surfaces;l (2) a flaky material; and (3) a powdered or finely crystalline material. f f

A lubricant with which we hate had much. success is castor oil,'both the raw. and b1own varieties. By blown castor' oil we mean thatv either the flaky ingredients or powdery ingredients. All three must be combined for the utmost all around utility; the oil acting as'lubricant and vehicle; the flaky materialy acting to physically block off or dam the larger avenues of leakage; and the smaller powdery particles functioning to block off the tiniest avenues of leakage. With only the oil and powdery filler constituent the whole mixture may be forced by internal pressure out the avenues of leakage past they threads; with only the oil and the flakelike constituent, the oil may be forced out around the individual flakes.

product which is obtained by the oxidation or polymerization 4of ordinary raw-castor oil irre-` spective of the manner or the degree of oxidation or polymerization. Castor oil and especially blown castor oil has a great number of chemical and physical properties which make .it ideally suited for the application herein de scribed. Among these are (1) .high viscosity; (2) high film strength; (3) high resistance to chemical change on aging (especially true for the blownl variety due to its already-oxygensaturated state) (4) strong affinity for metallic surfaces; (5) properties not materially affected by small proportions of dissolved mineral oil or grease which may have been initially present on threaded surfaces. The purposeof the oil in our mixture is two-foldin that it acts (1) as a vehicle for the other two ingredients, and (2) as a non-drying, non-hardening, strongly adherentlubricant which keeps the metallic surfaces out of contact. z

The` second or flaky ingredient mentioned above has the purpose of blocking offany avenues of fluid escape which may exist in the threads by reason of improper machining or otherwise. Threads of chrome-nickel steel ya1- No special process'need be employed in mixing our compound except that itis obviously important that the materials be blended with rea- Aninert powdery material, such as barium sul- Y phate, 10 to 80 per cent by Weight An inert flaky material, such as powdered minum, l@ to 10 per centby weight An inert adhesive, non-drying oil, such oil, the remainder In the accompanying triangular graph, th area ABCD'represents compositions. of sealing mixtures containing castor oil, barium sulphate,

alu-

and aluminum powder in the proportions which'- function according to our invention as hereinbefore described. Beyond the'boundaries of the area ABCD, mixtures are obtained which exhibit entirely different properties because they have either too much ortoo little of one or the other of the ingredients. If too much barium sulphate or aluminum powder is used, v,the paste is too thick to be applied evenly and difficulty will be experienced in causing the material to yflow completely into the fissures in the threads; if too little is used, the condition of pure oil will be Y approachedA and accordingly the joint will leak.

While we have mentioned specific chemicals as ingredients in our novel sealing compound we vagain point outthat they are given only by way of illustration and that our compound consists broadly of the combination of these threematerials: any viscous, non-drying, non-hardening liquid lubricant; any finely divided flaky ingredient, and any powdery or finely crystalline material, allthree being diflicultly soluble in the common chemicals .which are ordinarilyy con-v veyed through metal pipes of .thetype described.

as` castor q 2,324,729 n n n i Neither do `we wish oiirnii the useof olirina-l i l `2, In asealing cementgthe combination zon-mf teria] to stainless `steel threaded joints asili; is sisting of a ternary mixtuieof castor eil, pow# i equally` applicable to threaded jointe` i'nadeioffA `lciered,lcza.`1i\;l11fi sulphate, andnely dividedlaiw any other material and may also beused adVan-"Q 4 minimi," the barium sulphate and libe. eesei niil 1 i iiageously` in joinus other than those employing; 5 'being in approximately equal quantitiesI and "the threads. Sincethe particular chemicals which n n nelydivided aluminum `comprising 1/2 to `10g] i `we have namedspecically have been mentioned, l percenjby weight of thewhole.'

6101113/ fOr `the sakeof more clearly` describing our, 3f In a non-hardeningcement, the combina- `ilrveliiolh We desire `to be limited only Within" l `tion consisting of" a-'ternary mixture of 0.5` to "101 theSCODe 0f the appended Claimsl10 per cent of nely divided akealuminm, i10f`1 Weclaimt l i i nuto 80 per` cent ofbarium sulphate powderpthe 1- A non'h'denng Cement 0f thelchalactel `remainder beingordinary raw castor oil. described, consisting of a. ternary mixtureof 0.5 i l i n i L to 1Q lper centoi finely divided flake aluminum,` l ROBERT SCHRH .n

` 10`to 8013er cent ofbarimsulphate powdrfand" L5` i n n "-R0ERT W MANUELL 10120891/2 per centof blown castoroil. v l i i" f n 

